Body Mass Index (BMI) at Time of Diagnosis as a Prognostic Indicator in Patients with Newly Diagnosed Glioblastoma (GBM)

Abstract

Glioblastoma (GBM) is the most common primary brain cancer in adults with very poor prognosis. Metabolic drivers of tumorigenesis are highly relevant within the central nervous system, where glucose is the sole source of energy. The impact of obesity on survival outcomes in patients with GBM has not been well reported and some initial results are inconsistent. This study investigates the factor of body mass index (BMI) in patients diagnosed with GBM. This study evaluated the prognostic association of BMI with survival outcomes in patients with newly diagnosed GBM. Patientswith newly diagnosed GBM at our institution from 2015-2022 were included in this study. All patients were >18 years of age and received 60 Gy of radiation therapy with concurrent and adjuvant temozolomide following maximal safe resection. Through retrospective chart review, patient BMI at the time of diagnosis and overall survival (OS) were recorded. Analysis was done between patient groups of underweight/normal weight (BMI <25) and overweight/obese (BMI ≥ 25.00). The subgroup of overweight patients was also divided into subgroups of overweight (BMI 25.00-29.99) and obese (BMI≥30.00). A difference in clinical outcomes of overall survival was evaluated between the groups using Gehan-Breslow-Wilcoxon and log-rank tests. Atotal of 393 patients met inclusion criteria. Median age 57.3 years, range 18.8-92.7. 185 female and 208 were male. 120 patients had a BMI <25 and 273 had a BMI ≥ 25.00. Median survival in patients with BMI <25 was 24.90 months and in patients with BMI ≥ 25.00, 18.20 months (p = 0.0001; HR 0.6552, 95% CI 0.5299-0.8101). We further divided patients with BMI ≥ 25.00 to 25-29.99 (n = 152) and BMI≥30.00 (n = 121). Both groups' OS were significantly worse than patients with BMI < 25 (p = 0.006). There was no difference in survival outcomes between patients with a BMI 25.00-29.99 and BMI≥30.00, with median OS 19.0 months and 18.1 months, respectively. Patient baseline BMI <25 appears to be a prognostic indicator and correlates to improves overall survival for patients with newly diagnosed GBM. This study adds to the existing literature supporting overweight/obesity is associated with worse survival for GBM patients. Additional studies are warranted for further analysis of BMI and survival outcomes in GBM patients across patient demographics.